Mouth blisters can be caused by vitamin deficiencies, as well as trauma and wear and tear, poor diet, viral infections, hemangiomas, and more. 1.Massive Vitamin Deficiency:A deficiency of vitamin B and vitamin C, especially vitamin B2 and vitamin B6, can easily cause oral problems. Due to the lack of vitamin C, oral resistance will be reduced, and the lack of vitamin B2 and vitamin B6 will lead to oral mucosal lesions, such as ulcers or blisters. 2. Causes of trauma and abrasion: the mucous membrane of the inner wall of the mouth is thin, which can be caused by excessive chewing of hard objects or external forces, burns and other causes of blisters, which can be manifested as blisters on the inner wall of the mouth. 3. Bad dietary habits: eating spicy and stimulating foods in the usual diet, or partiality, lack of vitamins, can cause blistering of the inner wall of the patient’s mouth, if not corrected in time, can further form oral ulcers. 4. Viral infection: if infected with herpes simplex virus, it usually manifests as herpes on the oral mucosa and skin around the mouth, and therefore can manifest as blistering on the inner wall of the mouth. 5. Hemangioma: The oral cavity is a good place for hemangioma, which can be manifested as blisters on the inner wall of the mouth. If you have blisters in your mouth, it is recommended to go to the hospital as soon as possible for relevant examination and active treatment after clarifying the cause of the disease.